MORE than 85% of public housing tenants who had received help from a specialised homelessness agency would have a successful tenancy once they were granted housing, a new study has shown.

The Australian Institute of Health and Welfare examined 19,000 public housing tenants in NSW and Western Australia over two years from July 2011.

It found people with a history of homelessness were at the highest risk of losing a tenancy - followed by single parents or couples with children in their care.

Mental health, drug and alcohol, gambling and legal issues were also major factors in leases being cancelled.

"We found that the more days of support received from a homelessness service - be it prior to beginning a public housing tenancy, or during a tenancy - the more likely that the tenancy would be ongoing," AIHW spokesman Geoff Neideck said.

More than 85% of tenants helped at any time by a homelessness agency still had an ongoing tenancy at the end of the study in June 2013.

Almost all clients studied (90%) were on government payments or pensions, with employment rates at about 5%.